Greetings,

I have a 87 951, and I put a Yellow Top Optima battery on the car. If I park the car over 2-3 days, the battery would run out and I would need to jump start the car.

Would it be the alternator is old and needs to be replaced, or would the Yellow Top battery overworks the alternator so it couldn't be charged well?

Thanks in advance for any help,

With best regards,
- Alex.

 

How long did your previous battery last? Sounds like you have a drain somewhere.

 

Previous battery (bought from Kragan Auto Parts) last at least 2 to 3 weeks.

Does it also mean the Yellow Top Optima (compares to a regular battery) does not require extra workload from the alternator to charge?

Many thanks,

 

Maybe the yellow top wasn't in good shape when you bought it. I'd swap it at the store if they are local. I've heard of conventional batteries having defects, not sure about Optima.

 

The battery will not "over work" the alternator.

Alternator load (current output) is a function of not only the charge state of the battery. Alternator load is also a function of how much current is being drawn by the other electrical systems.

To determine if the alternator is chargine the battery, with the engine off connect a volt meter to the battery and take a voltage reading. Start the engine and read the voltage again. If the alternator is charging you should see at least 13.8 volts DC.

Since the battery is draining while the engine is shut down, you have a "parasitic drain," which simply means that something, or a combination of somethings is drawing current from the battery all of the time and is not being shut down when the ignition is off.

Common sources for parasitic currents are aftermarket alarm systems, aftermarket stereo head units, aftermarket stereo amps, radar detectors, navigation systems, and so forth.

Finally, make sure the battery and battery box are absolutely clean (external salt tracks conduct current), and all battery connections are clean and tight.

 

Thanks very much for the detailed explanation.

It is kind of intereting that whenever I start the car, the on-dash voltmeter will show about 13.5V. Then after driving for some distance (e.g. a 10 mile freeway trip to the office) it will drop to 11.8V and never go back up to 13.5.

When I go home after work and start the car, the voltmeter will go to 13V-13.5V again, and when I almost home it will drop back to 11.8V.

Does it tell something is wrong?

With best regards,

 

Have you had your altenator test for output? Stock should put out >90 amps, right?

 

Not recently, but now I think I am going to check it (fingers crossed )

Thanks again for the quick responses

Regards,

 

This is normal. When it moves up to 13.8 VDC it is recharging the battery. Once the batttery is charged up the O/P voltage drops to maintain the battery and keep the electrics going on the car.

It looks like something is still left on. Some people have had their glovebox lights left on ... make sure the switch turns off the light. If there is a problem with your temp switch for the fans ... the fans will stay on until the battery almost dies. If the turbo water pump connection gets wet the turbo water pump stays on thus killing the battery.

If you have not changed the pos and neg battery cables ... now is the time. Do a search for iceshark as he does sell a great set of cables.

Hope this helps,

 

Any noticable difference in using the Optima batts???

 

I love the yellow top in my camaro.
It seems to last forever.

when the one in my porsche dies I will be replacing it with a yellow top